Metal treatment



Patented Mar. 30, 1937 METAL TREATMENT Victor Conquest, Chicago, Ill.',assignor to Armour and Company, Chicago, 111., a corporation of IllinoisNo Drawing. Application "June 29, 1936,

Serial 20 Claims. (Cl. 91-68) This invention relates to the treatment ofmetal surfaces to provide them with a corrosion-resisting film and itcomprises, as new products, metal articles carrying a corrosionresistingfilm composed of a ketone having the general formula R-C-R' wherein R isa'closed ring radical and R is an aryl radical containing at least sixcarbon atoms; it further comprises processes wherein metal surfacessubject to atmospheric corrosion are coated with such ketones.

Various methods of providing'metal surfaces such as steel withcorrosion-resisting coatings have been proposed in the prior'art. Forexample, steel has been treated with many different chemical reagents toso modify the steel surface that an anti-rusting surface is presented tothe forces of atmospheric corrosion. Such metal treatment results in thedeposition on the surface of an extremely thin film which is notattacked by atmospheric moisture, oxygen, and

' similar substances ordinarily tending to rust the steel. All of theseso-called metal treatmentsare essentially surface reactions. They arenot to be confused with painting or otherwise applying protectingcoatings which do not actually modify the surface of the metal itself.Paints and like coating compounds merely form a coating on the surface.Should the paint chip oil, the exposed metal surface rusts or corrodesreadily. These metal treating processes are of great utility in thepre-treatment of metal surfaces prior to the application of ornamentalpaint films. For example, it is customary to rustproof steel automobilebodies before the application of lacquers thereto. This is to protectthe 4 metal surface in the event some of the lacquer film is chipped orscratched oil. I have now. discovered that so-called mixed ketones, thatis, ketones wherein one of the radicals attached to the carbonyl groupis a 45 closed ring radical such as phenyl, and the other I adical lsanalkyl radical containing at least six arbon atoms,- will. form adsorbedmolecular films on metal surfaces normally corroding or rusting in theatmosphere, that such films are- 0 substantially permanent, and thatsuch films protect the metal surface against corrosion; These filmsaremot, however, to be confused with coatings such as lacquers.Apparently metal surfaces treatedwith the ketones of'my invention 55actually unite with the ketone in some way.

, dicted.

toward atmospheric especially useful in the practice of myinvention.

can be demonstrated quite readily. When steelarticles, such asautomobile fenders, are immersed in, or, spraye'd'with a liquid mixtureof ketones of the class embraced within my invention, and the surfacethen drained to remove excess ketone so that the surface is apparentlyfree of any extraneous material, the metal'is highly anti-corrosive. Infact when the treated metal surfaces are actually subjected to theactio-n of good solvents for the ketone films thereon, the

film cannot be removed. This indicates to me that the metal surface hasadsorbed a thin film,

probably of molecular dimensions. Adsorption phenomena of this type arein the realmof surface chemistry and cannot, of course, be pre- That.the metal surface will adsorb molecular films of these ketones issurprising although the adsorption of gas, liquids and solids bysurfaces is, of course, a recognized physicalchemical phenomenon.

The ketones which I use. to protect the metal against corrosion are allhighly stable substances chemically. They are. insoluble in water andare not oxidized by ainmoisture, light; or carbon dioxide and similaracidic compounds normally present in the atmosphere. Their inertnessinfluences. makes them P T-Eur o n Moreover, they are relativelyinexpensive since Y they can be prepared from the cheap fatty. acidsavailable in large quantities. H

When practising my invention all that is necessary is to cause the metalsurface to contact with the ketone in any suitable manner. As will bepointed out in detail present1y,,all of the ketones used inmy inventionare either liquids orwaxlike solids. When using normally liquid'keton'esfor the treatment of the metal surface, I simply immerse the metalarticle in a bath of the ketone or mixtures there0f, and wipe off, ordrain off, any excess liquid." Surface adsorption is almostinstantaneous. Phenyl hexyl ketone is liquid and is a satisfactorymaterial to use. One of the best ketonic compounds is that'prepared fromcom peratures as low as 0 C. and the metal article can be immersedtherein, or the metal surface can be sprayed with the ketonic material.

painted, lacquered or otherwise ornamented with coating compounds inways well known. 'Allof the usual coating compounds adhere strongly tothe pre-treated surface.

I shall now list many ketones which used. in the practice of myinvention. For economic reasons many of these ketones would not be usedsince they are somewhat expensive in comparison with ketones like theabove-described mixtures of xylyl-alkyl ketones, the phenylheptadecy'lketones, andothers produced in part from benzene and naphthalene. But inorder to indicate the breadth of my invention, I am listing manydifierent types of ketones falling within my generic disclosure. Asstated, in most instances I find it more economical to use the cheapketones, or various mixtures thereof, such as phenyl heptadecyl ketone,mixtures thereof with xylyl heptadecyl ketone, etc. Proportions in suchmixtures are not at all critical; whether mixtures are to be used willbe governed largely by the cost of the ketones. I

A representative list of ketones I can use is as follows: i

Phenyl heptadecyl ketone I p- Tolyl heptadecyl ketone m-Xylyl heptadecylketone -p-Xylyl heptadecyl ketone m-Xylyl pentadecyl ketone p-Tolylpentadecyl ketone p-Methoxyphenyl pentadecyl ketone p-Ethoxyphenylpentadecyl ketone Phenyl undecyl ketone p'-Chlorphenyl undecyl ketonep-Methoxyphenyl heptadecyl ketone p-Methoxyphenyl undecyl ketonep-Phenoxyphenyl heptadecyl ketone p-Phenoxyphenyl tridecyl ketonep-Phenoxyphenyl undecyl ketone v p-Nitro phenoxyphenyl heptadecyl ketonep-Methyl phenoxyphenyl heptadecyl ketone Alkyl phenones from lard fattyacids. Alpha naphthyl heptadecyl ketone Alpha naphthyl pentadecyl ketoneAnthracyl heptadecyl ketone (mixtures) Biphenyl heptadecyl ketoneBiphenyl tridecyl ketone Biphenyl undecyl ketone p-Methyl biphenylheptadecyl ketone p-Chlorbiplienyl heptadecyl ketone Furyl heptadecylketone Furyl undecyl ketone Methyl furyl heptadecyl. ketone Dibenzoiurylheptadecyl ketone I Dibenzofuryl undecyl ketone.

Consequently, in the appended claims I define my ketonic materialsbroadly as those in which one of the radicals attached to carbonyl is aclosed ring radical and the other is analkyl radical having at least sixcarbon atoms.

Likewise, in the appended claims I wish to define the metal treatedbroadly. Apparently all metals will adsorb molecular layers of myketonic their alloys do not however corrode or rust as readily as ironor steel. Copper and aluminum will, of course form oxide layers unlessotherwise protected and my invention can be used to keep copper fromdiscoloring as a result of atmospheric influences. My invention isespecially useful in'the treatment of steel and'iron surfaces, and itcan even be used to prevent silver from tarnishing. Silver articlestarnish readily due to contact with hydrogen sulphide in the atmosphere.Anjadsorbed layer of ketonic material on the silver prevents this. Sincethe ketonic films are of molecular dimensions they cannot, of course, bedetected by visual inspection and the treated silver does not have agreasy or waxy feel. 4

It will be apparent that many other metal surfaces are benefited by theprocesses of the present invention. Ornamental aluminum on the exteriorof'buildings can be kept shiny'if pre-treatedwith my ketones prior toexposure to the atmosphere. Aluminum foil, and other metal foils usedfor heat insulation can be maintained shiny so that a maximum amount ofheat wherein R a closed ring compound and R is an alkyl radical havingat least six carbon atoms. I

2. The article as in claim 1 wherein R is an aryl group. 3. The articleas in claim 1 wherein R is a phenyl radical.

4. The articleas 'in claim 1 wherein R is a xylyl radical.

5. The article as in claim 1 wherein the ketonic material is a mixtureof isomeric xylyl-alkyl ketones in which the alkyl group contains atleast eight carbon atoms.

6. A steel article having a surface provided with a corrosion-resistingfilm of a ketonic material composed of at least one ketone having theformula wherein R is' a closed ring compound and R is an alkyl radicalhaving at least six carbon atoms.

.tonic material is a mixture of isomeric xylylalkyl ketones in which thealkyl group contains at least eight carbon atoms.

11. The process of protecting the surface of metals against corrosionwhich. includes treatposed of at least one ketone having the formula.

wherein R is a closed ring compound and R is 14. The process as in claim11 wherein R is a xylyl radical.

15. The process as in claim 11 wherein the ketone is a mixture ofisomeric xylyl-alkyl ketones in which the alkyl group contains at leasteight carbon atoms.

16. The process of, protecting the surface of steel articles againstcorrosion which includes treating the surface with a ketonic materialcomposed of at least one ketone having the formula wherein R is a-closedring compound and R is an alkyl radical having at least six carbonatoms.

17. The process as in claim 16 wherein R is a phenyl radical.

18. The process as in claim 16 wherein R is a phenyl radical.

19. The process as xylyl radical.

20. The process as in claim 16 wherein the ketone is a mixture ofisomeric xylyl-alkyl ketones in which the alkyl group contains at leasteight carbon atoms.

in claim 16 wherein R is a VICTOR CONQUEST.

